General wireless alarm systems on the market today typically consist of alarm devices that work on a mobile phone network, such as e.g. on a GSM-network, which are very vulnerable. This is due to the fact that there are various different easily accessible obstructing devices, downloadable e.g. via Internet, by means of which it is possible to obstruct or block e.g. a GSM- or another type of wireless network. Obstructing wireless networks with these types of devices has brought up a challenge that has not yet been solved in a way that alarm systems based on a mobile phone network or other wireless networks could reliably fulfill their purpose. Because the above mentioned blocking devices are cheap and widely available on the market, and because using them does not require special skills e.g. in radio technology, it is thus clear that protecting one's property or estate is not on a sufficient level when using wireless alarm systems according to the present technique.
For securing an alarm system a method is presented e.g. in Finnish patent No. 117992 that aims to enhance transmission security of an alarm, which method is based on the fact that the device for forwarding the alarm is set up with a subscriber identity module from a mobile phone operator that is not limited to operate in only one mobile phone network in the country in question. Functioning of the device for forwarding an alarm and its connectivity are being monitored by forming a test connection. An authority alarm is given by making an emergency call from the alarm forwarding device to an emergency central, in case the authority alarm fails to be transmitted through the alarm forwarding device's primary forwarding connection in a time limit set beforehand.
Especially based on the figures of said patent, it may be seen that said solution is especially targeted towards forwarding arrangements outside the site that is being monitored. In said patent, the blocking or obstructing of a wireless network as described in the beginning has not been in any way taken into account, even though said patent is based on the sending of an actual alarm wirelessly. As the solution according to said patent is based on the principle that in case of an alarm, the system tries to connect to a control centre, it can not secure a reliable functioning of the alarm system, especially in case of a wireless network blocking situation of the type described above or in addition to the above a possible obstruction situation of the electrical network.
Furthermore, in Finnish patent 120064 is presented a method and apparatus for forwarding notifications from a remote device to a control node. This solution is based on the sending of a notification automatically between a remote node and control node, the above being connected with each other by a data network. In the method, a remote node is determined to the control node, which nodes are registered to a server together. An event notification concerning the remote node is ordered to the control node from the server. The control node notes the time taken by the order and repeats the order. An external signal is noted in the remote node, and a message is sent from the remote node to the control node. The control node checks the presence of information in the remote node and registers the message.
The solution above is based on acquiring information from the remote node (the site to be monitored), to a so called SIP-server, whereby the server makes a connection attempt to the remote node in a determined time, and the remote node gives the information to the server to be forwarded by the same. If necessary, the remote node can give a quick message to the server to be forwarded by the same. Also in this solution it is necessary to use e.g. a GSM- or an internet connection. In this solution, the SIP-server is in a managing position, which is why it also creates a bottleneck for the functioning of this solution due to the same reasons mentioned above regarding patent FI 117992. Therefore, with this solution, either an alarm system can not be sufficiently secured in case of a previously described obstruction of a wireless network, and/or an electrical network.
The solutions described above therefore share a similar function in a way that when recognizing an observation/alarm, they take a connection and make an alarm through a transmission route from the site to be monitored to outside thereof. In the implications of these solutions the used transmission servers, managing organs and other forwarding arrangements between the site to be monitored and the receiver of the alarm, form a critical entirety for the part of their functioning reliability, which may be severed by blocking operations especially focused on wireless networks and/or electrical network obstructing operations etc., due to which they thus prevent completely, or at least slow down receiving of an alarm. These systems are also technically demanding and expensive in both execution and management due to the complicated device compositions related thereto.